Creating composite assemblies, such as composite helicopter rotor blades, sometime requires a costly and time consuming process comprising curing particular composite components and assemblies and followed by assembling the cured components to form the overall composite assembly. In some cases, the composite assembly includes a structural member referred to as a “spar,” which may extend the axial length of the structure and provide support against loads applied to the structure. In the case of airfoil shaped blades or wings, the spar may support both the weight of the blade and any aerodynamic loads applied to the blade, such as lift and drag forces.
In some cases, the spar may be formed from a composite preform that is cured prior to assembly with the other components of the structure, such as skin assemblies in the case of composite blades. During this curing process, an inflatable bladder may be disposed within the uncured spar and expanded to help compact the layers of preformed composite material and remove any excess air bubbles or other voids included in the preform as the spar is cured at an elevated temperature within a precision mold. Once cured, the other components or “details” of the composite assembly are assembled with the spar. For instance, in the case of a blade, the outer skins and leading edge are assembled with the spar and then bonded in a subsequent curing process, sometimes referred to as the assembly “curing cycle” or “bond cycle.”
The assembly process requiring a relatively high level of precision in order to consistently achieve the tight tolerances in sizing and placement of all the components required to minimize any defects formed during the assembly process, such as voids or overly thick bond lines formed between components. Moreover, the placement and fitting of the components forming the composite assembly may need to be monitored and maintained for a period of time during the operational life of the composite assembly to ensure proper and adequate performance. For example, in the case of composite blades, the placement and sizing of the details may need to be monitored in order to ensure composite blade has maintained the proper contour.